The present invention relates to chelators for metals and, more particularly, to a pharmaceutical composition for oral administration of a mixture of chelators to a subject.
Chelating agents, or chelators, constitute a well known type of multifunctional organic compounds that are capable of forming complexes of multivalent metal ions such as, for example, calcium, magnesium zinc, iron, chromium, and lead. Chelators find use in a variety of commercial applications, for example, photographic processing solutions, to which they can be added to form soluble complexes with metal ions that would otherwise produce undesirable precipitates or sludges.
A well known and widely used chelator is ethylenediaminetetraacetic acid, (HO2CCH2)2NCH2CH2N(CH2CO2H)2, commonly referred to as EDTA, commercially available both as the free acid and as various salts, for example, disodium EDTA, tetrasodium EDTA, dipotassium EDTA, calcium disodium EDTA, etc. Other commercial chelators are the naturally occurring amino acid L-cysteine, HSCH2CH(NH2)CO2H, and its acetylated derivative N-acetyl-L-cysteine, HSCH2CH(NHCOCH3)CO2H, commonly referred to as NAC.
In addition to their industrial applications, chelators have also been extensively employed therapeutically in the treatment of human subjects. For example, injections of EDTA have been used to remove high levels of toxic lead from the bloodstream of individuals who have been exposed to lead paint. Intravenous injection of chelators has also been employed in the treatment of other medical conditions. For example, U.S. Pat. No. 5,114,974 to Rubin discloses the treatment of atherosciereosis with MgNa2EDTA.
Chelation therapy to remove potentially harmful metal ions from the body of an individual is today frequently proposed as a means for gaining and maintaining good health and avoiding surgery for heart disease. Although chelation therapy of human patients is most commonly carried out by intravenous injection, oral chelation therapy is also well known. For example, U.S. Pat. No. 5,080,906 to Carenzi et al. discloses a method and composition for oral administration of N-acetylcysteine (NAC).
Various formulations containing one or more chelators for oral administration are commercially available. Typically, these formulations contain a low dosage of chelators, along with a mixture of other purportedly beneficial ingredients. The list of ingredients for one such product, Life Glow Plus(trademark) from Vibrant Life contains, per capsule, 25 mg disodium dihydrate EDTA, 15 mg L-cysteine, and 15 mg NAC, and specified amounts of 48 additional substances, including other amino acids, vitamins, minerals, herbs, glandular substances, and xe2x80x9cspecial items.xe2x80x9d The recommended daily dosage of Life Glow Plus(trademark) is 20 capsules.
Another available oral chelation product is Kelation Plus(copyright) from Kelation Plus International, Jacksonville Fla., a powder packaged in individual daily servings and said to contain 26 pharmaceutical grade vitamins, minerals, amino acids, and glandulars. The list of 26 ingredients, all in unspecified amounts, for Kelation Plus(copyright) includes L-cysteine. A footnote to the ingredients list states: xe2x80x9cEDTA used as a preservative.xe2x80x9d
U.S. Pat. No. 6,114,387 to Cutler discloses a solid pharmaceutical composition for the oral administration of chelating agents to an individual that consists essentially of at least 100 milligrams of ethylenediaminetetraacetic acid (EDTA) or a molar equivalent amount of pharmaceutically acceptable salts or hydrated salts of EDTA, at least 75 milligrams of N-acetylcysteine (NAC), and an appropriate amount of at least one pharmaceutical formulating agent.
Lactoferrin is an 80 kDa mammalian iron-chelating glycoprotein that can be obtained on a commercial scale from the whey protein of cow""s milk. The anti-viral, anti-microbial, anti-cancer, and immune modulating/enhancing effects of orally administered lactoferrin have been extensively reported. Because many pathogenic bacteria require a supply of free iron to grow, they can, in the presence of the strongly iron-chelating lactoferrin, be inhibited or killed. For example, as reported in Shi et al., xe2x80x9cHuman Lactoferrin Binds and Removes the Hemoglobin Receptor Protein of the Peridontopathogen Porphyromonas gingivalisxe2x80x9d, J. Biol. Chem., 2000, Vol. 275, No. 39, pp. 30002-30008, lactoferrin exhibits an inhibiting action on growth of the bacteria responsible for gingivitis.
In regard to its anti-cancer effects, lactoferrin exhibits a capability for inhibiting angiogenesis, a well-establish prerequisite for tumor growth, as discussed in Norby et al., xe2x80x9cOrally Administered Bovine Lactoferrin Systemically Inhibits VEGF165-Mediated Angiogenesis in the Ratxe2x80x9d, Int. J. Cancer, 2001, Vol. 91, pp. 236-240. Also, as reported in Kuhara et al., xe2x80x9cOrally Administered Lactoferrin Exerts an Antimetastatic Effect and Enhances Production of IL-18 in the Intestinal Epitheliumxe2x80x9d, Nutrition and Cancer, 2000, Vol. 38, No. 2, pp. 192-199, lactoferrin has been found to exert a significant inhibiting effect on the lung colonization of colon 26 carcinoma.
The anti-viral, anti-cancer, and anti-microbial effects of lactoferrin, as well as its antioxidant characteristics, are discussed in Brink, xe2x80x9cLactoferrin: The Bioactive Peptide that Fights Diseasexe2x80x9d, Life Extension magazine, October 2000, which also includes an extensive listing of recent publications regarding the beneficial effects of lactoferrin.
There remains a need for a convenient, orally administered pharmaceutical composition that contains an effective dosage of a combination of selected chelators, in particular, ethylenediaminetetraacetic acid, N-acetyl-L-cysteine, and lactoferrin, without included extraneous ingredients that may impair their effectiveness. This need is met by the present invention.
In accordance with the present invention, a solid pharmaceutical composition for the oral administration of chelating agents to an individual consists essentially of: at least 100 milligrams of ethylenediaminetetraacetic acid (EDTA) or a molar equivalent amount of pharmaceutically acceptable salts or hydrated salts of EDTA, at least 75 milligrams of N-acetyl-L-cysteine, at least 10 milligrams of lactoferrin, and an appropriate amount of at least one pharmaceutical formulating agent.
The pharmaceutical composition of the present invention provides a convenient alternative to intravenous injection of chelating agents, which is time-consuming and requires visitation to a medical facility.